class CPU:
    def run(self):
        print("CPU开始运行")
    def stop(self):
        print("CPU停止运行")

class Disk:
    def run(self):
        print("硬盘开始工作")
    def stop(self):
        print("硬盘停止工作")

class Memory:
    def run(self):
        print("内存通电")
    def stop(self):
        print("内存断电")

class Computer:
    def __init__(self):
        self.CPU=CPU()
        self.disk=Disk()
        self.memory=Memory()
    def run(self):
        self.CPU.run()
        self.disk.run()
        self.memory.run()

    def stop(self):
        self.CPU.stop()
        self.disk.stop()
        self.memory.stop()

#Client
computer=Computer()
computer.run()
computer.stop()